#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define TEST_ASSERT(left, right, success_msg, fail_msg)                        \
  do {                                                                         \
    if ((left) == (right)) {                                                   \
      printf("[PASS] %s\n", success_msg);                                      \
    } else {                                                                   \
      printf("[FAIL] %s: Expected 0x%lx, but got 0x%lx\n", fail_msg,           \
             (unsigned long)(right), (unsigned long)(left));                   \
    }                                                                          \
  } while (0)

static int signal_received = 0;

void signal_handler(int signo) {
  if (signo == SIGINT) {
    printf("\nReceived SIGINT (Ctrl+C)\n");
    signal_received = 1;
  }
}

void print_signal_mask(const char *msg, const sigset_t *mask) {
  printf("%s: ", msg);
  for (int signo = 1; signo < NSIG; ++signo) {
    if (sigismember(mask, signo)) {
      printf("%d ", signo);
    }
  }
  printf("\n");
}

// 获取当前屏蔽字的函数
unsigned long get_signal_mask() {
  sigset_t sigset;
  if (sigprocmask(SIG_BLOCK, NULL, &sigset) == -1) {
    perror("sigprocmask");
    return -1; // 返回错误标记
  }

  // 将信号集编码为位掩码
  unsigned long mask = 0;
  for (int i = 1; i < NSIG; i++) {
    if (sigismember(&sigset, i)) {
      mask |= 1UL << (i - 1);
    }
  }
  return mask;
}

int main() {
  sigset_t new_mask, old_mask;
  sigemptyset(&old_mask);

  // 注册 SIGINT 的信号处理函数
  if (signal(SIGINT, signal_handler) == SIG_ERR) {
    perror("signal");
    exit(EXIT_FAILURE);
  }
  printf("Signal handler for SIGINT is registered.\n");
  signal_received = 0;
  kill(getpid(), SIGINT);
  sleep(5);

  TEST_ASSERT(signal_received, 1, "SIGINT was received",
              "SIGINT was not received");
  signal_received = 0;

  // 初始化新的信号集，并将 SIGINT 添加到其中
  sigemptyset(&new_mask);
  sigaddset(&new_mask, SIGINT);

  // 打印 new_mask 的值
  print_signal_mask("new_mask", &new_mask);

  // 屏蔽 SIGINT
  if (sigprocmask(SIG_BLOCK, &new_mask, &old_mask) < 0) {
    perror("sigprocmask - SIG_BLOCK");
    exit(EXIT_FAILURE);
  }

  // 打印 old_mask 的值
  print_signal_mask("old_mask", &old_mask);

  // 检查 SIGINT 是否被屏蔽
  unsigned long actual_mask = get_signal_mask();
  unsigned long expected_mask = (1UL << (SIGINT - 1));
  TEST_ASSERT(actual_mask, expected_mask, "Signal mask is as expected",
              "Signal mask mismatch");

  printf("SIGINT is now blocked.\n");
  signal_received = 0;
  // 向当前进程发送 SIGINT
  kill(getpid(), SIGINT);

  // 等待 5 秒，以便测试 SIGINT 是否被屏蔽
  sleep(5);
  TEST_ASSERT(signal_received, 0, "SIGINT was blocked",
              "SIGINT was not blocked");
  signal_received = 0;
  // 恢复原来的信号屏蔽字
  if (sigprocmask(SIG_SETMASK, &old_mask, &old_mask) < 0) {
    perror("sigprocmask - SIG_SETMASK");
    exit(EXIT_FAILURE);
  }
  print_signal_mask("old_mask returned", &old_mask);

  // 检查 SIGINT 是否被解除屏蔽
  actual_mask = get_signal_mask();
  expected_mask = 0;
  TEST_ASSERT(actual_mask, expected_mask, "Signal mask is as expected",
              "Signal mask mismatch");

  printf("SIGINT is now unblocked.\n");

  signal_received = 0;
  kill(getpid(), SIGINT);

  // 等待 5 秒，以便测试 SIGINT 是否解除屏蔽
  sleep(5);
  TEST_ASSERT(signal_received, 1, "SIGINT was received",
              "SIGINT was not received");

  printf("Exiting program.\n");
  return 0;
}
